Invasives

Invasives

Sun Oct 25, 2009 8:49 pm

Here is a list for Canada of some of the invasive plants that you should NOT plant in your garden. Only plant invasives if you are an avid gardener who keeps up with his/her weeding. These plants can really get away from you and choke out local flora and fauna.

garlic mustard and japanese honeysuckle shrub are the two I battle most, but we also have around here tons of Tree-of-Heaven and rosa multiflora... And lots of woods including my little spot over-run with English ivy.

Just as a nutty permaculture perspective: a lot of things that are considered invasive are excellent permaculture plants. Scotch broom is a popular example. A nitrogen fixer. Indicating low N in the soil. A good plant to keep around until you have something better to plant there - then when you take it out, the soil is mighty rich.

And then there's the whole thing about douglas fir trees being the invasive some some time ago (500 years?)

How can we ever consider an invasive plant permaculture, when it is not ecologically sustainable by definition? If the non-native plant replaces enough native biomass, then according to what I understand, we will get attending losses of insects (usually around 25-30% of insects in any area won't have enzymes to digest the non-native plants). Then we lose some birds or frogs or fish that were counting on those bugs. And the plants that were counting on the insect to pollinate them don't reproduce and guess who fills that spot? Ad infinitum, ad nauseum, ad mortis.

Isn't sustainability part of permaculture? So shouldn't preserving the ecosystem be the very first step in permaculture?

A decent answer to your question is about two chapters in a book. A complete answer would be a few books.

First, there is the whole thing about native plants: for nearly all natives, at one point they were invasives! So then when you say "native" you really have to define a point in time.

Next, if we wanna stick to scotch broom: while it is considered an invasive, didn't it move into N-deficient land where there was little else growing. Further, with the scotch broom showing up, didn't it improve the eco system?

I like Bill Cullina's definition of pre-European plants as native. Sure, corn is introduced, but not a rampant replacer of more suitable variety and provenance... the real issues are Eurasians moved here by, well, us. Gardeners. Farmers. Us.

Cytisus "improved" this N-deficient land, but what was the ecosystem it is replacing? Perhaps low N is a definition of such a system. For instance the Pacific Northwest is particularly plagued with it, and it is often boreal forest soils there. Boreal forests tend toward fungal soil systems, fungal systems tend to be acidic and tend to keep the the N as ammoniacal sourcing, made available to evergreen trees through mycorhizal symbiots (evergreen trees are about the most reliant on mycorrhizae, as a group). Not a lot of plant available N; horrible for growing a crop. But who's trying to grow a crop? This soil wants to be a forest...

So if by improvement you mean changing over an ecosystem to suit our needs, then by all means, broom is a winner. But where do we draw the lines? How do we even begin to know the long term effects of such shifting? How do we arrest our eco-transformation if we want to? These are the questions that keep me up. Until we have better understanding of ecosytemic construction (mankind has yet to make a working sustainable ecosystem by design) shouldn't we be taking care of the working ones we have? And taking notes rather than doling out suggestions? Aren't we invasives of a sort ourselves?

Your opinion is neither obnoxious or unwanted. It is a very real topical concern and a conversation we all should be having, even with ourselves, before we choose plants for our gardens and fields. Thanks for bringing it up...

There's the difference between good-behaved non-natives vs. invasives that take over.

Difference between a stray seed or few, blown in on Hurricane X winds vs. wholescale planting by humans in the name of LANDSCAPING, which subsequently escapes cultivation -- maybe due to seed transported on the windshield well of exhaust fume pumping vehicle.

Non-native INVASIVES that DOESN'T support native wildlife, taking over an eco-system and resulting in marked decline in wildlife diversity.

Non-natives that also accidentally introduced non-native pests that are perfectly happy to eat NATIVE plants -- like Japanese Beetles, etc. If they would just stick to eating the invasives from home like Japanees bittersweet and honeysuckle...

What about Phyllostachys bamboo? Clonally invasive but only comes to seed about every hundred years, certainly not on the menu for any native species I know (even soil biology has a tough time with this one). Yet we could crop it in small, incredibly dense culture, make paper from the hurds, flooring, utensiles, cloth, plastic, etc. etc. from the plants, cut it down every year and get a bigger getter crop next year, saving the land we don't use for wilderness, yet it remains by your defination, an invasive. Should we grow it here?

And ain't I a stinker?

See, while I don't like broom in particular, (or beach rose or barberry or burning bush) for it's prolific seed generation and attendent distribution systems (feeding the birds is a double-edged sword here), I don't think we should rule any plants out until the cost/benefit analysis is in. There are ways we can work with some of these plants. But there are others that need to be reviewed, curtailed, and disposed of. The industry will NOT effectively self-regulate; they have made that clear by their response to resonable and considered legislation, and considering the messes self-regulation have led to lately (anyone for a quick lesson in credit default swaps?), it's probably not the best idea anyway.

That leaves we, the people, to figure out what is right and good, and purchase accordingly. This is at it's heart an ethical question, with some scientific overtones to be sure, but mostly a question of right and wrong, good and bad. In matters of ecological right and wrong, I always fall back to the Land Ethic of Aldo Leopold... I offer a bit here...

This thumbnail sketch of land as an energy circuit conveys three basic ideas:

1.That land is not merely soil. 2.That the native plants and animals kept the energy circuit open; others may or may not, 3.That man-made changes are of a different order than evolutionary changes, and have effects more comprehensive than is intended or foreseen These ideas, collectively, raise two basic issues: Can the land adjust itself to the new order? Can the desired alterations be accomplished with less violence?

Can our non-native plants fit in these parameters? IF they can fit into a niche with little or no replacement of existing species, IF they do not overtax available resources, IF they are not favored by humans above the original citizens of the biota to a point of advantage, THEN they MIGHT fit, assuming no other changes in the biota that exacerbate any point of Aldo's or my criteria.

Lot of ifs, but I think the bamboo fits. So never say never, there are always exceptions. But let's make sure from top to bottom of the food chain first...

How do you do that? (You keep generally inspiring me to think and re-think exactly the sort of things I want to think about... )

Bamboo is precisely the one invasive plant that I've been struggling with Re: to plant or not to plant. It's on the menu for ME! (not necessarily native species, I grant) I can also see me using it for garden support structures and other uses. Obviously not so much paper and other more intensely processed uses in my case, but useful none-the-less... AS LONG AS I CAN KEEP AHEAD OF IT.

That last big IF, as well as DH's rather strong objections AND realistic despair over the likelihood of any subsequent homeowner's willingness to keep up with it (and therefore, the downward tendency to property value)... you get the idea. It doesn't help that on a frequently used route to a local mall, there is a house that is DISAPPEARING behind a solid stand of bamboo. I should take a photo while it's still there -- the old lady who owned the house passed away couple of years ago, and it very likely that the nephew who inherited the house will be doing "something" about the bamboo.

Bamboo does not sprout from a culm once the culm has been apically arrested (science talk for "Cut the top and it's stops growing, above the soil, anyway) The Chinese control stands by simply kicking over any culms outside the desired area in early spring... they snap easy when they are young and full of water (edible stage)

So containing our roots is the issue. There is commercially available bamboo barrier, but you need to dig a four foot trench to install it, and it doesn't sound like DH is going to pitch in to that extent, if at all. So how about a fifty five gallon blue plastic food drum, bottom perfed full of holes, a few inches of gravel, then soil from the hole, and then your boo shoots? Leave about an inch or two of the rim above grade (those roots will hop shorter, but still easily taken care of, in any stead). Still not a small hole, but hire some local kids (if there are any not inside on their Gameboys)

Should be enough shoots and poles for most folk; if not, repeat process. Easily taken out or transplanted, contained nicely and without chems or undue toil. I will be sure to warn you about flowering, but if you are using Phyllostachys, and I remember right, we should have a couple, eight or nine decades to go...

Invasives are often about how they are handled; good practices lead to good things, bad practices lead to bad things. Some are simply not controllable and shouldn't be grown or used based on that. You know the ones; look in your woods and fields...

Nature doesn't waste an invasive disaster. It's the humans that suffer, along with other animals higher up the food chain.

Case in point: the earthworm. It came here through Jamestown, and radically altered North American ecosystems at breakneck speeds. The indigenous humans couldn't keep up, but the invading humans needed earthworms for their farming techniques. Preserving habitat is a choice only a human could make. And a good one, if you are are a human who depends on measured change. It's not the concept of altering nature that is wrong, it's doing it without knowing the consequences first. Which unfortunately, is what we tend to do.

But let's not get too righteous. WE are invasive. Let's just make sure we don't work against ourselves by creating more imbalance than we can handle.

There's something new growing in the Helpful Gardener Forum! Become a part of ithere!

And there, my friends, is the opening for a book on the subject. And that book will have to sacrifice accuracy for brevity. So then you write 100 volumes on the subject. And while those 100 volumes might cover all currently knowledge, the next 40 years will prove a third of it wrong.

It is a rich space.

Another view: if you are talking about a garden, well, okay, you can pluck out the things you don't want rather easily. But if you are talking about something more along the lines of 100 acres, the challenges shift.

In a permaculture system, I think scotch broom is such an excellent example. It is greatly feared by so many and yet it has so many excellent values. And where it pops up on its own, it clearly is adapted to that patch of soil. If you cut it to have something else use that space, it has a lot of N-rich biomass. It actually makes soil better for other plants.

I think if I was headed out to take some plants out, I would take out a douglas fir before I would take out scotch broom. The douglas fir is allelopathic (makes the soil icky for other plants).

So then we get into the whole natives thing.

And then we can examine the space: of all of the things we eat, how much are native?

And then we can examining the space: what might be the overall expense of postponing the inevitable homogenization of all species. I think I tried to figure this out for just one state once and it would be 10's of trillions of dollars to establish and then trillions of dollars to maintain. And all we can do is slow it down.

I think it is grand to have museum plots of natives and to maintain species that might otherwise become extinct. But requiring folks to eliminate invasives from their land is just another form of tax for goofiness. That said, I do think there are some allelopathic species worth attempting to control. But ....

Well, as I said .... this topic is far too rich for a forum thread.

I think money and effort could be 30 times more efficient with just a little more intelligence behind the efforts.

And, as with many things polyculture and diversity resolve a lot of this stuff.

I think that this is the root of permaculture. And it has been demonstrated many times. I know that there have been several demonstrations in australia. A famous case is where a desert was transformed and "thornless honey locust" was one of the species used. Only when thornless honey locust drops seeds a lot of the babies have thorns. So the new problem is that the area is infested with the nasty thorns. So they went from an area with nothing to having a thorn problem.

Another rather famous example: have you seen the short animation "the man who planted trees" - apparently based on a true story.

And then there is geoff lawton's interesting work in ... I think it is Jordan? There is a followup youtube showing that same land seven years later. They cared for it for two years and then it was abandoned for five. It was an open wasteland of salt, sand and rocks and now .... wow ... jungle-ish.

We cannot make this sort of thing in a sterile test tube, but permaculture does teach us just enough so we can set up some scaffolding for nature to fill in the blanks.